Regulatory Assets and Liabilities (Schedule of Regulatory Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Regulatory Assets [Line Items]
Current regulatory assets	$ 1,530	$ 1,009
Long-term regulatory assets	6,446	6,088
Southern California Edison
Regulatory Assets [Line Items]
Current regulatory assets	1,530	1,009
Long-term regulatory assets	6,446	6,088
Total regulatory assets	7,976	7,097
Southern California Edison | Regulatory balancing and memorandum accounts
Regulatory Assets [Line Items]
Current regulatory assets	1,315	798
Long-term regulatory assets	1,133	981
Southern California Edison | Power contracts
Regulatory Assets [Line Items]
Current regulatory assets	194	189
Long-term regulatory assets	271	434
Southern California Edison | Other
Regulatory Assets [Line Items]
Current regulatory assets	21	22
Long-term regulatory assets	113	62
Southern California Edison | Deferred income taxes, net of liabilities
Regulatory Assets [Line Items]
Long-term regulatory assets	4,349	4,026
Southern California Edison | Pensions and other postretirement benefits
Regulatory Assets [Line Items]
Long-term regulatory assets	81	87
Southern California Edison | Unamortized investments, net of accumulated amortization
Regulatory Assets [Line Items]
Long-term regulatory assets	115	119
Southern California Edison | Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Long-term regulatory assets	136	142
Southern California Edison | Environmental remediation
Regulatory Assets [Line Items]
Long-term regulatory assets	$ 248	$ 237